JPH0417366Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an air filling circuit for an air suspension vehicle, and is intended to improve ride comfort when the vehicle is not loaded.

<Prior Art> As shown in FIG. 2, the rear wheels of a truck are suspended by air springs 1 and 2 provided on the left and right sides of the vehicle, respectively. The compressed air in the air suspension tank 3 is distributed to the right and left sides via a right-side air supply path 5 in which a leveling valve 4 is provided and a left-side air supply path 7 in which a leveling valve 6 is provided. The air is supplied to the air springs 1 and 2. When cargo is loaded onto the loading platform of a truck equipped with such an air suspension and the loading platform is lowered, the leveling valves 4 and 6 are opened and fresh compressed air is sent from the air suspension tank 3 to the air springs 1 and 2. As a result, the air spring 1, which has been compressed once due to loading the cargo,
2 extends to a steady state and the loading platform also returns to its normal position.
When the steady state returns, the leveling valves 4 and 6 close. Also, when the loading platform is tilted in the width direction due to cargo being placed on one side, the leveling valve on the deeply sunken side opens and compressed air is sent to the air spring on that side to keep the loading platform level.

<Problem that the invention aims to solve> By the way, when the carrying load is small (or the car is empty), the weight of the loading platform decreases, but the torsional rigidity of the car body frame is high, so the air pressure in either the left or right air spring decreases. Even when the vehicle is lowered, the vehicle body does not tilt and maintains a horizontal state, and the distance between the cargo platform and the axle does not change. Therefore, even if the air pressure on either the left or right side decreases, the leveling mechanism will not operate and compressed air will not be supplied. Therefore, the leveling valves 4 and 6 do not operate, and the spring constants of the air springs 1 and 2 remain different. This results in poor riding comfort.

In view of the above-mentioned prior art, an object of the present invention is to provide an air filling circuit that maintains the air pressure of the left and right air springs 1 and 2 at a constant value even when the vehicle is not loaded to ensure riding comfort.

<Means for Solving the Problems> The configuration of the present invention that achieves the above object is to supply air from the compressed air source to the right side and the left side through the right side and left side air supply paths each having a leveling valve. In air suspension vehicles where the vehicle body is suspended by supplying compressed air to the springs, the compressed air source is connected to the right and left air springs through new air supply channels, ie bypass channels for the right and left sides. Furthermore, it is characterized in that valves for the right side and the left side are interposed in the bypass paths for the right side and the left side, which automatically enter the flow state when the air pressure in the air spring becomes below a certain value.

<Example> Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 shows a first embodiment of the invention. In the figure, 1 and 2 are right and left air springs, 3 is an air suspension tank, 4 and 6 are leveling valves, and 5 and 7 are right and left air supply passages. Furthermore, in this embodiment, bypass passages 1 for the right side and the left side are provided as new air supply passages that communicate the air suspension tank 3 and the air springs 1 and 2.
A valve 12 for the right side is provided in the bypass passage 10, and a valve 13 for the left side is provided in the bypass passage 11, respectively. Valve 1
2 has a piston 12b in the valve body 12a,
12c, piston connection part 12d, spring 12e, O
It is configured with a ring 12f. The piston 12c has a larger pressure receiving area than the piston 12b, and both pistons 12b and 12c are connected by a piston connecting portion 12d and can slide within the piston body 12a. The spring 12e is connected to the pistons 12b, 12
When the piston 12b is at the left end position, the bypass passage 10 is closed, and when the piston 12b is moved to the right position, air can flow through the bypass passage 10. This valve 12 communicates with the air spring 1 via a pilot channel 14 for the right side. On the other hand, the valve 13 includes pistons 13b, 13c,
Piston connection part 13d, spring 13e, O ring 1
3f. The piston 13c has a larger pressure receiving area than the piston 13b, and both pistons 13b and 13c are connected by a piston connecting portion 13d and can slide within the piston body 13a. The spring 13e biases the pistons 13b and 13c to the left in the figure, and when the piston 13b is at the left end position, the bypass passage 11 is closed and the piston 13
When b moves to the right, air can flow through the bypass path 11. This valve 13 communicates with the air spring 2 via a pilot channel 15 for the left side.

In this embodiment, under normal conditions when the air pressures of the air springs 1 and 2 are equal to or higher than a certain pressure P, the piston 12b of the valve 12 is moved between the air pressure P and the spring 12.
e to the left to close the bypass path 10. Similarly, the piston 13b of the bypass 13
Therefore, the bypass path 11 is closed.

On the other hand, when the leveling valves 4 and 6 are not activated and the air supply passages 5 and 7 are closed when no cargo is loaded, when the air pressure in the air spring 1 falls below the constant value P, the piston 12b of the valve 12 It is moved to the right by the air pressure from the air suspension tank 3, and compressed air is supplied to the air spring 1 via the bypass path 10. When compressed air is supplied through the bypass path 10 and the air pressure in the air spring 1 exceeds a certain value P, the piston 12b moves to the left due to the pressure P and the spring force of the spring 12e, closing the bypass path 10. It will be done. In this way, even when the leveling valve 4 is not opened and the load is not loaded, compressed air is automatically supplied to the air spring 1 via the bypass path 10, and the air pressure of the air spring 1 can be kept constant, and the spring constant can be kept constant. can be held. Of course, valve 1 also applies to air spring 2.
3, compressed air is similarly supplied via the bypass path 11, making it possible to keep the air pressure of the air spring 2 constant and the spring constant constant.

In the above embodiment, if an auxiliary tank is connected to each air spring 1, 2 in order to increase the air capacity of the air springs 1, 2 and improve the spring characteristics, the pilot passages 14, 15 are connected to the auxiliary tank. It is better to connect it to This is because the air pressure in the auxiliary tank fluctuates less than the air pressure in the air springs 1 and 2.

<Effects of the invention> As specifically explained above based on the embodiments, according to the present invention, the right side is equipped with a valve that automatically enters the flow state when the air pressure in the air spring falls below a certain value. Compressed air is sent to the right and left air springs using bypass passages for the left and right sides, so the air pressure in the right and left air springs remains constant even when no load is loaded, and the spring constant is uniform, resulting in a comfortable ride. gets better. Moreover, since the valve is constructed from only mechanical members, there is no need for complicated electrical circuits, electrical sensors, etc., and the valve can be constructed at low cost.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional technique. In the drawing, 1 and 2 are air springs, 3 is an air suspension tank, 4 and 6 are leveling valves, 5,
7 is an air supply path, 10 and 11 are bypass paths, 1
2 and 13 are valves, and 14 and 15 are pilot passages.

Claims (1)

[Scope of Claim for Utility Model Registration] Supplying compressed air from a compressed air source to air springs arranged on the left and right sides of a vehicle through left-side and right-side air supply passages in which leveling valves are respectively installed. In an air suspension vehicle in which the vehicle body is suspended by: a bypass passage for the left side which is arranged in parallel with the air supply passage for the left side and has one end communicating with the compressed air source and the other end communicating with the air spring on the left side; and a bypass passage for the left side which is connected to the bypass passage for the right side. a first piston that opens and closes the bypass passage for the right side and is slidably interposed in one of the valve bodies for the right side, and a first piston that opens and closes the bypass passage for the right side, and a second piston slidably interposed in the other of the pistons, connected to the first piston, and having a larger pressure receiving area than the first piston; a right-hand valve consisting of a spring that biases the first piston in the closing direction; a left-hand valve body interposed in the left-hand bypass passage; a third piston that is movably interposed and opens and closes the bypass passage for the left side, and a third piston that is movably interposed in the other valve body for the left side and is connected to the third piston and that is connected to the third piston; a left-hand valve comprising a fourth piston having a larger pressure-receiving area than the third piston; and a spring provided in the left-hand valve body and biasing the third piston in a closing direction; is connected to the other end of the right-hand valve body, and the other end is connected to the right-hand air spring, and one end is connected to the left-hand valve body, and the other end is connected to the left-hand air spring. and pilot passages for the left side which are communicated with each other, and when the air pressure in the right side air spring becomes less than a predetermined value, the first piston is moved by the pressure of the compressed air source and the valve for the right side moves to the right side. The bypass passage for the right side is opened and compressed air is supplied to the air spring on the right side, and when the air pressure in the air spring on the right side exceeds the predetermined value, the bypass passage for the right side is closed. When the air pressure in the left air spring becomes less than a predetermined value, the third piston is moved by the pressure of the compressed air source to open the left side bypass passage and supply compressed air to the left air spring, and An air filling circuit for an air suspension vehicle, characterized in that the air filling circuit for an air suspension vehicle is configured to close the left bypass passage when the air pressure in the left air spring exceeds the predetermined value.